Commit a6ed4ff8 authored by Matthias Clasen's avatar Matthias Clasen
Browse files

layout: Implement tab alignments

Implement the other tab alignments by adjusting
the tab width as we go.

Based on an old patch by Itai Bar-Haim.

This also includes a fix for the previously
supported left tab alignment in the presence
of indent.

Fixes: #34
parent 60ae4ac4
......@@ -3262,6 +3262,7 @@ pango_layout_line_leaked (PangoLayoutLine *line)
*****************/
static void shape_tab (PangoLayoutLine *line,
ParaBreakState *state,
PangoItem *item,
PangoGlyphString *glyphs);
......@@ -3367,54 +3368,54 @@ ensure_tab_width (PangoLayout *layout)
}
}
/* For now we only need the tab position, we assume
* all tabs are left-aligned.
*/
static int
get_tab_pos (PangoLayout *layout,
int index,
gboolean *is_default)
static void
get_tab_pos (PangoLayoutLine *line,
int index,
int *tab_pos,
PangoTabAlign *alignment,
gboolean *is_default)
{
gint n_tabs;
PangoLayout *layout = line->layout;
int n_tabs;
gboolean in_pixels;
int offset = 0;
if (layout->alignment != PANGO_ALIGN_CENTER)
{
if (line->is_paragraph_start && layout->indent >= 0)
offset = layout->indent;
else if (!line->is_paragraph_start && layout->indent < 0)
offset = - layout->indent;
}
if (layout->tabs)
{
n_tabs = pango_tab_array_get_size (layout->tabs);
in_pixels = pango_tab_array_get_positions_in_pixels (layout->tabs);
if (is_default)
*is_default = FALSE;
*is_default = FALSE;
}
else
{
n_tabs = 0;
in_pixels = FALSE;
if (is_default)
*is_default = TRUE;
*is_default = TRUE;
}
if (index < n_tabs)
{
gint pos = 0;
pango_tab_array_get_tab (layout->tabs, index, NULL, &pos);
pango_tab_array_get_tab (layout->tabs, index, alignment, tab_pos);
if (in_pixels)
return pos * PANGO_SCALE;
else
return pos;
*tab_pos *= PANGO_SCALE;
}
if (n_tabs > 0)
else if (n_tabs > 0)
{
/* Extrapolate tab position, repeating the last tab gap to
* infinity.
*/
/* Extrapolate tab position, repeating the last tab gap to infinity. */
int last_pos = 0;
int next_to_last_pos = 0;
int tab_width;
pango_tab_array_get_tab (layout->tabs, n_tabs - 1, NULL, &last_pos);
pango_tab_array_get_tab (layout->tabs, n_tabs - 1, alignment, &last_pos);
if (n_tabs > 1)
pango_tab_array_get_tab (layout->tabs, n_tabs - 2, NULL, &next_to_last_pos);
......@@ -3428,22 +3429,19 @@ get_tab_pos (PangoLayout *layout,
}
if (last_pos > next_to_last_pos)
{
tab_width = last_pos - next_to_last_pos;
}
tab_width = last_pos - next_to_last_pos;
else
{
tab_width = layout->tab_width;
}
tab_width = layout->tab_width;
return last_pos + tab_width * (index - n_tabs + 1);
*tab_pos = last_pos + tab_width * (index - n_tabs + 1);
}
else
{
/* No tab array set, so use default tab width
*/
return layout->tab_width * index;
/* No tab array set, so use default tab width */
*tab_pos = layout->tab_width * index;
}
*tab_pos -= offset;
}
static int
......@@ -3460,7 +3458,7 @@ line_width (PangoLayoutLine *line)
{
PangoLayoutRun *run = l->data;
for (i=0; i < run->glyphs->num_glyphs; i++)
for (i = 0; i < run->glyphs->num_glyphs; i++)
width += run->glyphs->glyphs[i].geometry.width;
}
......@@ -3484,14 +3482,24 @@ showing_space (const PangoAnalysis *analysis)
return FALSE;
}
static void break_state_set_last_tab (ParaBreakState *state,
PangoGlyphString *glyphs,
int width,
int tab_pos,
PangoTabAlign tab_align);
static void
shape_tab (PangoLayoutLine *line,
ParaBreakState *state,
PangoItem *item,
PangoGlyphString *glyphs)
{
int i, space_width;
int current_width;
int tab_pos;
PangoTabAlign tab_align;
int current_width = line_width (line);
current_width = line_width (line);
pango_glyph_string_set_size (glyphs, 1);
......@@ -3499,6 +3507,7 @@ shape_tab (PangoLayoutLine *line,
glyphs->glyphs[0].glyph = PANGO_GET_UNKNOWN_GLYPH ('\t');
else
glyphs->glyphs[0].glyph = PANGO_GLYPH_EMPTY;
glyphs->glyphs[0].geometry.x_offset = 0;
glyphs->glyphs[0].geometry.y_offset = 0;
glyphs->glyphs[0].attr.is_cluster_start = 1;
......@@ -3509,22 +3518,28 @@ shape_tab (PangoLayoutLine *line,
ensure_tab_width (line->layout);
space_width = line->layout->tab_width / 8;
for (i=0;;i++)
for (i = 0; ; i++)
{
gboolean is_default;
int tab_pos = get_tab_pos (line->layout, i, &is_default);
get_tab_pos (line, i, &tab_pos, &tab_align, &is_default);
/* Make sure there is at least a space-width of space between
* tab-aligned text and the text before it. However, only do
* tab-aligned text and the text before it. However, only do
* this if no tab array is set on the layout, ie. using default
* tab positions. If use has set tab positions, respect it to
* the pixel.
* tab positions. If the user has set tab positions, respect it
* to the pixel.
*/
if (tab_pos >= current_width + (is_default ? space_width : 1))
{
glyphs->glyphs[0].geometry.width = tab_pos - current_width;
g_debug ("shape_tab: tab %d, align %d, width %d\n",
i, tab_align, glyphs->glyphs[0].geometry.width);
break;
}
}
break_state_set_last_tab (state, glyphs, current_width, tab_pos, tab_align);
}
static inline gboolean
......@@ -3608,12 +3623,65 @@ struct _ParaBreakState
int hyphen_width; /* How much space a hyphen will take */
GList *baseline_shifts;
PangoGlyphString *last_tab;
int last_tab_width;
int last_tab_pos;
PangoTabAlign last_tab_align;
};
static void
break_state_set_last_tab (ParaBreakState *state,
PangoGlyphString *glyphs,
int width,
int tab_pos,
PangoTabAlign tab_align)
{
state->last_tab = glyphs;
state->last_tab_width = width;
state->last_tab_pos = tab_pos;
state->last_tab_align = tab_align;
}
static gboolean
should_ellipsize_current_line (PangoLayout *layout,
ParaBreakState *state);
static void
get_decimal_prefix_width (PangoItem *item,
PangoGlyphString *glyphs,
const char *text,
int *width,
gboolean *found)
{
PangoGlyphItem glyph_item = { item, glyphs, 0, 0, 0 };
int *log_widths;
int i;
const char *p;
log_widths = g_new (int, item->num_chars);
pango_glyph_item_get_logical_widths (&glyph_item, text, log_widths);
*width = 0;
*found = FALSE;
for (i = 0, p = text + item->offset; i < item->num_chars; i++, p = g_utf8_next_char (p))
{
if (g_utf8_get_char (p) == '.')
{
*width += log_widths[i] / 2;
*found = TRUE;
break;
}
*width += log_widths[i];
}
g_free (log_widths);
}
static PangoGlyphString *
shape_run (PangoLayoutLine *line,
ParaBreakState *state,
......@@ -3623,7 +3691,7 @@ shape_run (PangoLayoutLine *line,
PangoGlyphString *glyphs = pango_glyph_string_new ();
if (layout->text[item->offset] == '\t')
shape_tab (line, item, glyphs);
shape_tab (line, state, item, glyphs);
else
{
PangoShapeFlags shape_flags = PANGO_SHAPE_NONE;
......@@ -3661,6 +3729,33 @@ shape_run (PangoLayoutLine *line,
glyphs->glyphs[0].geometry.x_offset += space_left;
glyphs->glyphs[glyphs->num_glyphs - 1].geometry.width += space_right;
}
if (state->last_tab != NULL)
{
int w;
g_assert (state->last_tab->num_glyphs == 1);
/* Update the width of the current tab to position this run properly */
w = state->last_tab_pos - state->last_tab_width;
if (state->last_tab_align == PANGO_TAB_RIGHT)
w -= pango_glyph_string_get_width (glyphs);
else if (state->last_tab_align == PANGO_TAB_CENTER)
w -= pango_glyph_string_get_width (glyphs) / 2;
else if (state->last_tab_align == PANGO_TAB_DECIMAL)
{
int width;
gboolean found;
get_decimal_prefix_width (item, glyphs, layout->text, &width, &found);
w -= width;
}
state->last_tab->glyphs[0].geometry.width = MAX (w, 0);
}
}
return glyphs;
......@@ -3681,19 +3776,45 @@ insert_run (PangoLayoutLine *line,
run->glyphs = glyphs;
else if (last_run && state->log_widths_offset == 0 &&
!(run_item->analysis.flags & PANGO_ANALYSIS_FLAG_NEED_HYPHEN))
run->glyphs = state->glyphs;
{
run->glyphs = state->glyphs;
state->glyphs = NULL;
}
else
run->glyphs = shape_run (line, state, run_item);
if (last_run)
if (last_run && state->glyphs)
{
if (state->log_widths_offset > 0)
pango_glyph_string_free (state->glyphs);
pango_glyph_string_free (state->glyphs);
state->glyphs = NULL;
}
line->runs = g_slist_prepend (line->runs, run);
line->length += run_item->length;
if (state->last_tab && run->glyphs != state->last_tab)
{
/* Adjust the tab position so placing further runs will continue to
* maintain the tab placement. In the case of decimal tabs, we are
* done once we've placed the run with the decimal point.
*/
if (state->last_tab_align == PANGO_TAB_RIGHT)
state->last_tab_width += pango_glyph_string_get_width (run->glyphs);
else if (state->last_tab_align == PANGO_TAB_CENTER)
state->last_tab_width += pango_glyph_string_get_width (run->glyphs) / 2;
else if (state->last_tab_align == PANGO_TAB_DECIMAL)
{
int width;
gboolean found;
get_decimal_prefix_width (run->item, run->glyphs, line->layout->text, &width, &found);
state->last_tab_width += width;
if (found)
state->last_tab = NULL;
}
}
}
static gboolean
......@@ -3801,6 +3922,15 @@ compute_log_widths (PangoLayout *layout,
pango_glyph_item_get_logical_widths (&glyph_item, layout->text, state->log_widths);
}
static int
tab_width_change (ParaBreakState *state)
{
if (state->last_tab)
return state->last_tab->glyphs[0].geometry.width - (state->last_tab_pos - state->last_tab_width);
return 0;
}
/* Tries to insert as much as possible of the item at the head of
* state->items onto @line. Five results are possible:
*
......@@ -3916,7 +4046,6 @@ process_item (PangoLayout *layout,
if (state->remaining_width < 0 && !no_break_at_end) /* Wrapping off */
{
insert_run (line, state, item, NULL, TRUE);
DEBUG1 ("no wrapping, all-fit");
return BREAK_ALL_FIT;
}
......@@ -3932,6 +4061,16 @@ process_item (PangoLayout *layout,
width += state->log_widths[state->log_widths_offset + i];
}
if (layout->text[item->offset] == '\t')
{
insert_run (line, state, item, NULL, TRUE);
state->remaining_width -= width;
state->remaining_width = MAX (state->remaining_width, 0);
DEBUG1 ("tab run, all-fit");
return BREAK_ALL_FIT;
}
if (!no_break_at_end &&
can_break_at (layout, state->start_offset + item->num_chars, wrap))
{
......@@ -3946,31 +4085,32 @@ process_item (PangoLayout *layout,
else
extra_width = 0;
if ((width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs)) &&
if ((width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs) ||
(state->last_tab && state->last_tab_align != PANGO_TAB_LEFT)) &&
!no_break_at_end)
{
PangoGlyphString *glyphs;
DEBUG1 ("%d + %d <= %d", width, extra_width, state->remaining_width);
insert_run (line, state, item, NULL, FALSE);
glyphs = shape_run (line, state, item);
width = pango_glyph_string_get_width (((PangoGlyphItem *)(line->runs->data))->glyphs);
width = pango_glyph_string_get_width (glyphs) + tab_width_change (state);
if (width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs))
{
insert_run (line, state, item, glyphs, TRUE);
state->remaining_width -= width;
state->remaining_width = MAX (state->remaining_width, 0);
/* We passed last_run == FALSE to insert_run, so it did not do this */
pango_glyph_string_free (state->glyphs);
state->glyphs = NULL;
DEBUG1 ("early accept '%.*s', all-fit, remaining %d",
item->length, layout->text + item->offset,
state->remaining_width);
return BREAK_ALL_FIT;
}
/* if it doesn't fit after shaping, revert and proceed to break the item */
uninsert_run (line);
/* if it doesn't fit after shaping, discard and proceed to break the item */
pango_glyph_string_free (glyphs);
}
/*** From here on, we look for a way to break item ***/
......@@ -4055,7 +4195,7 @@ retry_break:
glyphs = shape_run (line, state, new_item);
new_break_width = pango_glyph_string_get_width (glyphs);
new_break_width = pango_glyph_string_get_width (glyphs) + tab_width_change (state);
if (num_chars > 0 &&
layout->log_attrs[state->start_offset + num_chars - 1].is_white)
......@@ -4316,6 +4456,10 @@ process_line (PangoLayout *layout,
state->remaining_width = -1;
else
state->remaining_width = state->line_width;
state->last_tab = NULL;
state->last_tab_align = PANGO_TAB_LEFT;
DEBUG ("starting to fill line", line, state);
while (state->items)
......
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